Margin Plots of Response for Pairs of Factors

USAGE:
       margin.plot(x.factor, response, group, ...,
               orient = "default", average = "full")
ARGUMENTS:
x.factor:   factor whose margins are to be plotted on the x-axis.
       Factor  levels  are  plotted  below  the marginal means or
       effects.
response:   numeric vector.
group:    factor whose levels will be separate traces.
...:   optional specification of other parameters to be passed to
       plotting routines.
orient:   "default" = default (as in interaction.plot),  "switch"
       =  switch plot orientation of x.factor and group, "both" =
       plot both ways.  "full" = use response,  "reduced"  =  use
       predicted values from reduced (additive) model.

VALUE:
       a plot will be created showing the requested  function  of
       responses  for  each level of the `x.factor' at each level
       of the `group'.  By default, lines for each value  of  the
       `group'  are drawn in different styles so that they may be
       more easily distinguished.

SEE ALSO:
       `tukey.plot', `margin.plot.lm'.

EXAMPLES:
       > attach(catalyst)
       > margin.plot(Conc, Yield, Cat)
       > detach()